For vertical motors that objectively have axial force, angular contact ball bearings are mostly used, that is, the axial load-bearing capacity of the bearing body is used to balance the downward axial force generated by the deadweight of the vertical motor rotor.
In the structural design of the motor bearing system, the angular contact ball bearing generally bears the role of balancing the axial force and positioning the bearing at the same time; no matter whether the angular contact ball bearing is installed at the top or the bottom, the bearing is balancing the downward axial force generated by the rotor’s deadweight, that is, when the angular contact ball bearing is installed at the bottom of the motor, the bearing has an upward lifting effect on the rotor; and when the bearing is installed at the top of the motor, the bearing has a pulling effect on the rotor. Therefore, for vertical motors, a set of single-row angular contact ball bearings is generally used.
Theoretically, single-row bearings can bear radial loads and unidirectional axial loads. The standard contact angles of this type of bearings are 15°, 25° and 40°. The larger the contact angle, the greater the ability to bear axial loads. However, the smaller the contact angle, the more conducive to high-speed rotation. Therefore, the contact angle of the bearing should be comprehensively considered in combination with the motor speed.
Double row angular contact ball bearings are divided into two structures: one outer ring and two inner rings and one outer ring and one inner ring. The structure is that two single row angular contact ball bearings are combined on the back and share the inner ring and outer ring, which can withstand radial load and bidirectional axial load. This type of bearing is mainly used in machine tool spindles, high-frequency motors, gas turbines, oil pumps, air compressors, printing machinery, etc.
In practical applications, single-row angular contact bearings in back-to-back (DB) and face-to-face (DF) combinations, as well as double-row bearings, can withstand both radial loads and bidirectional axial loads. However, single-row angular contact bearings in tandem configuration (DT) are only suitable for applications where the unidirectional axial load is large and the rated load of a single bearing is insufficient.
In the actual application conditions of the motor, in addition to the axial force during the operation of the motor, if the axis misalignment caused by the bending factors of the shaft or housing is also considered, self-aligning bearings can also be used.
Post time: Nov-05-2024